Laser Tilt Measurement for Solder Bump Defect Detection
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Solution Overview
Problem
Current methods for inspecting the connection between surface-mounted components and integrated circuit boards are time-consuming, resource-intensive, and often fail to detect defects until after the reflow process, leading to potential short circuits or mechanical failures.
Innovation Solution
A non-destructive inspection apparatus using laser light to measure the height and tilt of electronic components relative to a substrate, allowing for the detection of attachment defects without individual inspection of each bump-terminal connection, facilitating fast and efficient post-production quality control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional inspection methods (x-ray, acoustic microscopy, functional testing) are used to detect bump defects, then measurement precision is improved, but productivity deteriorates due to time-consuming individual inspection of each bump-terminal connection
Solution Approach 1:
The inspection method segments the inspection process into two levels: (1) rapid tilt measurement of the entire electronic component using laser light to identify suspicious regions, and (2) detailed inspection only of those specific regions showing abnormal tilt. This segmentation allows the system to maintain high productivity while preserving measurement precision for critical areas.
Solution Approach 2:
The patent applies preliminary action by performing a rapid tilt measurement scan of the entire component before conducting detailed inspection. This preliminary tilt data identifies which bump-terminal connections require further investigation, allowing the system to prepare inspection priorities in advance and avoid time-consuming full-component detailed inspection.
2Reliability
If individual bump-terminal connections are inspected to ensure connection integrity, then reliability is improved, but loss of time increases due to the large number of bumps requiring inspection
Solution Approach 1:
The patent extracts only the essential information needed for defect detection by measuring tilt angles of electronic components relative to the substrate. Instead of inspecting each bump-terminal connection individually, the system extracts component-level tilt data that indicates potential connection problems, significantly reducing inspection time while maintaining reliability through targeted follow-up inspection of suspicious areas.
Solution Approach 2:
The patent introduces tilt measurement as an intermediary indicator of connection integrity. Rather than directly inspecting each bump-terminal connection, the system uses component tilt relative to the substrate as an intermediate measure that correlates with connection quality. This intermediary approach enables rapid assessment of connection integrity without time-consuming direct inspection of each connection point.
3Manufacturing precision
If bump dimensions are measured prior to reflow process, then manufacturing precision is maintained, but reliability deteriorates because defects emerge subsequent to reflow
Solution Approach 1:
The patent performs preliminary tilt measurement after the reflow process to detect defects that emerged during assembly. By measuring component tilt relative to the substrate after reflow, the system identifies connections that may have deteriorated during the heating and cooling process, enabling post-reflow quality assurance without compromising earlier manufacturing precision controls.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method enables reliable detection of defective connections, improving production efficiency and identifying post-assembly defects that conventional techniques miss, by measuring height profiles and tilt data to assess the integrity of solder bumps and component alignment.
Implementation Method 1
a laser light source for emitting laser light toward an electronic component to be inspected
Implementation Method 2
laser detection means for detecting the height of an inspection point of the device on the basis of the laser beam reflected from said electronic component
Data Source
AI summary
The present disclosure includes techniques and apparatus for making non-contact differential measurements of various dimensions of electronic components surface mounted on circuit boards. Tilt data relating to the electronic components is derived from the differential measurements to provide an indication of the integrity of the electrical connection between the electronic components to the circuit board. The techniques and apparatus of the present disclosure make it possible to accomplish non-destructive inspection of the connection without individually inspecting each bump-terminal connection.